Today we have stumbled upon following article (and related post), that is promising huge framerate boost in Batman: Arkham City with GPU PhysX effects enabled by replacing certain APEX .dll file with same .dll, but from Mafia II title (which is also featuring APEX based GPU PhysX effects). We decided to perform a little research on this effect:

Author of this method is suggesting to replace original file APEX_Clothing_x86.dll, located in Batman: AC folder, with renamed APEX Clothing.dll from Mafia II installation. Both those libraries are used by APEX Clothing module (and are responcible for cloth and clothing simulation), but have different version – Batman’s .dll is related to APEX 1.1 and the one from Mafia II – APEX 1.0.

Thus, with APEX 1.0 library cloth assets in Batman are not recognized and not simulated – they are simply appearing on level in frozen state, hovering above the ground (like carpets and posters on a screenshot below).

Disabled cloth simulation is giving you desired fps boost, but you can achieve same effect by setting “Hardware Accelerated PhysX” option to “Normal” – this will switch off all cloth and clothing simulation, leaving only particle PhysX effects, without necessity to mess up the .dlls.

To measure the effect on performance, we have tested the game using various combination of .dlls and PhysX settings (High in-game settings, DX 9).

Batman: AC .dll

Mafia II .dll

PhysX High

min: 26 fps

max: 94 fps

average: 52 fps

min: 33 fps

max: 117 fps

avarage: 74 fps

PhysX Normal

min: 33 fps

max:117 fps

average: 71 fps

min: 40 fps

max: 119 fps

average: 74 fps

As we expected, there is almost no difference in framerate between “tweaked” .dlls on “High PhysX” settings and original .dlls on “Normal PhysX” settings, since effect is similar – disabled cloth simulation.

Nothing like “magic tweak that increases fps by using files from older game, because new one is hobbled by purpose” as one may expect.

Sum – Pros:

Performace boost.

PhysX cloth objects are not removed completely, as on “Normal” PhysX settings.

Sum – Cons:

Frozen PhysX cloth objects without proper physical interaction may look out of place.

Older APEX .dll may decrease game stability and disable cloth simulation, that is not part of GPU PhysX effects.

Same effect can be achieved by switching PhysX option to “Normal”, without any potential negative backwash.

One Response to 'Investigation: boosting fps in Batman: Arkham City with APEX .dlls from Mafia II'

One last word: why during test min/max framerate is slightly better with APEX 1.0 .dll ?
Because in scene with ice gun curtains are simulated as cloth even on Normal PhysX settings and 1.1 .dll, but completely disabled with 1.0 dll